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Biomedical subjects

S Jacob

Publications and source records attributed to S Jacob.

208 records · Page 12Linked to original sources
PubMedDate not supplied

Context-dependent effects of steroid chemosignals on human physiology and mood.

We examined the physiological and psychological effects of nanomolar amounts of steroids applied directly under the nose (Delta4,16-androstadien-3-one and 1,3,5,(10),16-estratetraen-3-ol). These potential human chemosignals were not consciously discernible in a strong-odor carrier (clove oil and propylene glycol). In a double-blind, within-subject, repeated-measures experiment with 65 subjects, we demonstrated that both steroids produced sustained changes in digit skin temperature and palmar skin conductance (an indicator of sympathetic nervous system tone) while the subjects were completing psychological questionnaires or reading. These effects, however, did not follow the sex-stereotyped pattern predicted by a sex attractant function. Both androstadienone and estratetraenol raised the skin temperature of men's hands and lowered it in women. Likewise, each steroid increased skin conductance, with a significantly greater effect on women than men. Women's responses were observed only in the sessions run by the male tester, an effect that may or may not be solely attributable to tester sex. Men's responses, in contrast, were not affected by this difference in socioexperimental condition. Similarly, women experienced an immediate increase in positive mood only in the presence of the male tester, while men's responses were unaffected by this socioexperimental context. One source of this sex difference may be the fact that the majority of women were in the late follicular phase of their menstrual cycle. Although it is premature to classify these steroids as pheromones, our data suggest that they function as chemosignals that modulate autonomic nervous system tone as well as psychological state.

Adolescent↗
PubMedDate not supplied

Relationship between serum adiponectin concentration and intramyocellular lipid stores in humans.

The recently identified adipocytokine adiponectin has been shown to improve insulin action and decrease triglyceride content in skeletal muscle (by stimulating lipid oxidation) in mice. In the present study, we tested the hypothesis that high serum concentrations of adiponectin are associated with lower intramyocellular (IMCL) fat content by promoting lipid oxidation in humans. IMCL-content in predominantly non-oxidative tibialis anterior muscle and oxidative soleus was determined by proton magnetic resonance spectroscopy in a cross- sectional study involving 63 healthy volunteers. In a second set of experiments, changes in IMCL in both muscles were measured after a three days dietary lipid challenge (n = 18) and after intravenous lipid challenge (n = 12) with suppressed lipid oxidation under hyperinsulinemia. Adiponectin serum concentrations were found to be negatively correlated with IMCL in the oxidative soleus muscle (IMCL [sol]) (r = - 0.46, p < 0.001) independent of measures of obesity, but not with IMCL in the non-oxidative tibialis anterior muscle (IMCL [tib]) (p = 0.40). Adiponectin serum concentrations were negatively correlated with the observed increase in IMCL load after dietary lipid challenge in the tibialis (r = 0.53, p = 0.03) but not in the soleus muscle. During suppression of lipid oxidation by hyperinsulinemia, no effect of adiponectin on IMCL was observed in either soleus or tibialis muscle. Overall, the presented findings are consistent with the hypothesis that adiponectin promotes lipid oxidation in humans resulting in lower intracellular lipid content in human muscle. These results are consistent with animal data, where adiponectin could be shown to enhance lipid oxidation and reduce muscle triglycerides.

Adiponectin↗
PubMedDate not supplied

[Development of idiopathic scoliosis in electrostimulation treatment with an implantable system].

The results of electro-stimulation treatment in 46 patients with idiopathic scoliosis are compared with the results of daily short-term stimulation respectively Milwaukee-brace treatment. The over all results in cases treated with electro-stimulation were not worse than brace results. Therefore electro-stimulation treatment can be regarded as an alternative method to brace treatment with much better acceptance.

Adolescent↗
PubMedDate not supplied

Effect of glutathione modulation of the distribution and transplacental uptake of 2-[14C]-chloroacetonitrile (CAN) quantitative whole-body autoradiographic study in pregnant mice.

Chloroacetonitrile (CAN), a drinking water disinfectant by-product, has mutagenic and carcinogenic properties. CAN is known to deplete glutathione (GSH), and previous studies reported an enhanced molecular interaction of CAN after GSH depletion in the uterine and fetal tissues of mice. The present report may help to understand the potential mechanisms involved in such molecular interactions by examining the disposition, transplacental uptake and covalent interaction of the chemical in normal and GSH depleted pregnant mice (at 13th day of gestation). Both normal and GSH depleted (by administration of Diethylmaleate (DEM), 0.6 mL/kg, i.p.) pregnant mice were given an equitoxic i.v. dose of 2-[14C]-CAN(333 microCi/kg equivalent to 77 mg/kg). Animals were processed for whole-body autoradiography (WBA) at 1, 8 and 24 hr after treatment. Tissue distribution of radioactivity in the autoradiographs was quantitated using computer aided image analysis. With few exceptions, a rapid high uptake (at 1 hr) of radioactivity was observed in all major maternal (liver, lung, urinary bladder, gastrointestinal mucosa, cerebellum, uterine luminal fluid) and fetal (liver, brain) organs of both normal and GSH depleted mice. This pattern of distribution was observed, with lesser intensity, at 8 hr following treatment. At a later time period (24 hr), there was a significant higher retention and covalent interaction of radioactivity in GSH depleted mouse tissues especially in the liver as compared to normal mouse. This study suggests that 2-[14C]-CAN and/or its metabolites are capable of crossing the placental barrier. The observed higher uptake and retention of the radioactivity in the maternal liver, kidney, cerebellum, nasal turbinates and fetal liver may pose toxicity of the chemical to these organs. The increased covalent interaction of radioactivty in GSH depleted mice liver may indicate the potential utilization of GSH pathway by this organ in the detoxication of CAN derived metabolites and thus exerting hepatotoxicity.

Acetonitriles↗
PubMedDate not supplied

Mechanics of tarsal disintegration and plantar ulcers in leprosy by stress analysis in three dimensional foot models.

This paper describes three dimensional two arch models of feet of a normal subject and two leprosy subjects, one in the early stage and the other in the advanced stage of tarsal disintegration, used for analysis of skeletal and plantar soft tissue stresses by finite element technique using NISA software package. The model considered the foot geometry (obtained from X-rays), foot bone, cartilages, ligaments, important muscle forces and sole soft tissue. The stress analysis is carried out for the foot models simulating quasi-static walking phases of heel-strike, mid-stance and push-off. The analysis of the normal foot model shows that highest stresses occur at push-off over the dorsal central part of lateral and medial metatarsals and dorsal junction of calcaneus and cuboid and neck of talus. The skeletal stresses, in early state leprosy with muscle paralysis and in the advanced stage of tarsal distintegration (TD), are higher than those for the normal foot model, by 24% to 65% and 30% to 400%, respectively. The vertical stresses in the soft tissue at the foot-ground interface match well with experimentally measured foot pressures and for the normal and leprosy subjects they are the highest in the push-off phase. In the leprosy subject with advanced TD, the highest soft tissue stresses and shear stresses (about three times the normal value) occur in push-off phase in the scar tissue region. The difference in shear stresses between the sole and the adjacent soft tissue layer in the scar tissue for the same subject is about three times the normal value. It is concluded that the high bone stresses in leprosy may be responsible for tarsal distintegration when the bone mechanical strength decreases due to osteoporosis and the combined effect of high value of footsole vertical stresses, shear stresses and the relative shear stresses between two adjacent soft tissue layers may be responsible for plantar ulcers in the neuropathic leprosy feet.

Finite Element Analysis↗
PubMedDate not supplied

Incidences of simple and transferable drug resistance in Escherichia coli and Salmonella isolated from various foods: identification of a R plasmid in S. saint-paul.

A study of 1,043 strains of E. coli and 22 strains of Salmonella isolated from various foods in eastern France between the dates of June 1974 and December 1976 showed that 164 (15.6%) of E. coli and nine Salmonella were resistant to one or several drugs. Only 18 of the 83 resistant E. coli strains were able to transfer their resistance to tetracycline and some other drug resistance to E. coli K12 in vitro. A conjugative R plasmid has been identified by transfer experiments, incompatibility testing and agarose gel electrophoresis in a strain of multiresistant S. saint-paul.

Anti-Bacterial Agents↗
PubMedDate not supplied

[Alexithymia and memory: a more rigorous criterion for acceptance of recognition tasks?].

Alexithymia, the lack of words for affects, is often explained in a neurophysiological way. Many epidemiological studies have shown that this personality characteristic is a common one, frequently observed in the general population and, at least sometimes, context-dependent. Thus, alternatives to the split-brain alike hypothesis are required. In this paper, we focus on promising findings reported by Montreuil and Pedinielli (15): poorer alexithymic performances on memory taks in an incidental learning session. We tried to duplicate these results for a recognition task but failed to do so. Surprisingly, observed data show a trend in the opposite direction and alexithymic subjects perform better on distractors. Response times for the right answers (recognition of targets, elimination of distractors) are longer for this group. Taken together, these results suggest a difference in the managing of uncertainty. Alexithymic criterion for adoption/rejection of candidates to recognition is assumed to need a longer completion because of a greater number of attributes to recover in memory (considering a componential approach of representations in memory). Such a decision model explains why alexithymics perform better on elimination (they need more certainty) and why they show a slight decrease (unsignificant) on target acceptation (for a similar level of uncertainty alexithymics use a more rigorous criterion than the control group). From this decision model an alternative explanation is proposed for the results of Montreuil and Pedinielli in the recognition task. Further, it is suggested that a similar process might be implicated in the alexithymic difficulties about the translation of feelings into words. As it requires a matching between an ambiguous-continuous information (the inner feeling) and a consensual-discrete label (the emotional term), this process probably involves a great degree of uncertainty.

Adolescent↗